I saw the original with Frank Sinatra and Janet Leigh. I have not seen the remake.
The original is a good movie with Angela Lansberry's best role as Raymond's mother. Raymond's mother is the original mother from hell and Angela has great fun with the role. Lawrence Harvey is not as good as Raymond.
Brainwashing would not work as successfully as it does in the movie.
After John Kennedy's assassination Sinatra withdrew the film but at some point he allowed it to be shown. I can understand his withdrawing it but I'm glad he let it be shown again.